Genetic Variant MMADHC:p.Ser143Thr (chr2-149576487-C-G) – ACMG Classification: Uncertain_significance (0 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_015702.3(MMADHC):c.428G>C(p.Ser143Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,384 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S143I) has been classified as Benign.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MMADHC
NM_015702.3 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.533

Publications

0 publications found

Variant links:

Genes affected

MMADHC (HGNC:25221): (metabolism of cobalamin associated D) This gene encodes a mitochondrial protein that is involved in an early step of vitamin B12 metabolism. Vitamin B12 (cobalamin) is essential for normal development and survival in humans. Mutations in this gene cause methylmalonic aciduria and homocystinuria type cblD (MMADHC), a disorder of cobalamin metabolism that is characterized by decreased levels of the coenzymes adenosylcobalamin and methylcobalamin. Pseudogenes have been identified on chromosomes 11 and X.[provided by RefSeq, Nov 2008]

MMADHC Gene-Disease associations (from GenCC):

inborn disorder of cobalamin metabolism and transport
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen, Ambry Genetics
methylmalonic aciduria and homocystinuria type cblD
Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P

MMADHC links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.10464513).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_015702.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MMADHC	NM_015702.3	MANE Select	c.428G>C	p.Ser143Thr	missense	Exon 5 of 8	NP_056517.1	Q9H3L0

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
MMADHC	ENST00000303319.10	TSL:1 MANE Select	c.428G>C	p.Ser143Thr	missense	Exon 5 of 8	ENSP00000301920.5	Q9H3L0
MMADHC	ENST00000934249.1		c.551G>C	p.Ser184Thr	missense	Exon 6 of 9	ENSP00000604308.1
MMADHC	ENST00000422782.2	TSL:5	c.428G>C	p.Ser143Thr	missense	Exon 5 of 9	ENSP00000408331.2	F8WEC0

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461384

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727010

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33444

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26118

East Asian (EAS)

AF:

0.00

AC:

AN:

39626

South Asian (SAS)

AF:

0.00

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1111680

Other (OTH)

AF:

0.00

AC:

AN:

60368

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.070

BayesDel_addAF

Benign

-0.091

BayesDel_noAF

Benign

-0.37

CADD

Benign

(source)

DANN

Benign

0.96

DEOGEN2

Benign

0.21

Eigen

Benign

-0.41

Eigen_PC

Benign

-0.23

FATHMM_MKL

Uncertain

0.88

LIST_S2

Benign

0.76

M_CAP

Benign

0.016

MetaRNN

Benign

0.10

MetaSVM

Benign

-0.76

MutationAssessor

Benign

0.81

PhyloP100

0.53

PrimateAI

Benign

0.39

PROVEAN

Benign

-0.90

REVEL

Benign

0.17

Sift

Benign

0.24

Sift4G

Benign

0.64

Polyphen

0.0010

Vest4

0.12

MutPred

0.36

Gain of relative solvent accessibility (P = 0.1066)

MVP

0.63

MPC

0.032

ClinPred

0.23

GERP RS

2.2

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.12

gMVP

0.15

Mutation Taster

=94/6

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over